Written by the Fiveable Content Team • Last updated September 2025
Verified for the 2026 exam
Verified for the 2026 exam•Written by the Fiveable Content Team • Last updated September 2025
Definition
The index of refraction is a measure of how much light slows down when it passes through a medium. It quantifies the bending or change in direction that occurs as light travels from one medium to another.
This law describes how light bends when it passes from one medium to another, based on their respective indices of refraction.
Total Internal Reflection: This phenomenon occurs when light traveling in a high-index medium encounters an interface with a lower-index medium at an angle greater than the critical angle, causing all the light to reflect back into the higher-index medium.
Dispersion: Dispersion refers to the separation of white light into its component colors (rainbow) when passing through a prism or other transparent materials due to differences in refractive indices for different wavelengths.